Fort Hays State University FHSU Scholars Repository Sternberg Museum of Natural History Faculty Publications Sternberg Museum of Natural History 1-1-2005 Tylosaurus kansasensis, a new species of tylosaurine (Squamata, Mosasauridae) from the Niobrara Chalk of western Kansas, USA M. J. Everhart Fort Hays State University Follow this and additional works at: https://scholars.fhsu.edu/sternberg_facpubs Part of the Paleontology Commons Recommended Citation Everhart, M. (2005). Tylosaurus kansasensis, a new species of tylosaurine (Squamata, Mosasauridae) from the Niobrara Chalk of western Kansas, USA. Netherlands Journal of Geosciences, 84(3), 231-240. doi:10.1017/S0016774600021016 This Article is brought to you for free and open access by the Sternberg Museum of Natural History at FHSU Scholars Repository. It has been accepted for inclusion in Sternberg Museum of Natural History Faculty Publications by an authorized administrator of FHSU Scholars Repository. Netherlands Journal of Geosciences — Geologie en Mijnbouw | 84 - 3 | 231 - 240 | 2005 Tylosaurus kansasensis, a new species of tylosaurine (Squamata, Mosasauridae) from the Niobrara Chalk of western Kansas, USA M.J. Everhart | Sternberg Museum of Natural History, Fort Hays State University, Hays, Kansas 67601, USA. Email:
[email protected] Manuscript received: December 2004; accepted: January 2005 Abstract | Tylosaurus kansasensis sp. nov. is described herein on the basis of thirteen specimens collected from the Smoky Hill Chalk (upper Coniacian) of western Kansas, USA. The new species, originally designated Tylosaurus n. sp., co-occurred with T. nepaeohcus and exhibits a number of primitive characters that place it in a basal position in the mosasaur phylogeny. Among the key differences separating this species from other tylosaurines are a shortened, more rounded pre-dental process of the premaxilla, a distinctive quadrate lacking an infrastapedial process, and a parietal foramen located adjacent to the frontal-parietal suture.